Conventionally, rotors of dynamoelectric machines are treated to protect the rotor from rust, because rust, forming on the rotor, will bridge the air gap between the rotor and the facing stator teeth. Most commonly, zinc chromate is applied as a coating to the outside surface of the rotor. However, it has been found that rust, starting from between the rotor laminations, forces its way through the zinc chromate coating. It has also been common heretofore to coat the shaft with zinc phosphate, before the rotor was shrunk onto the shaft. The shaft so treated is then subjected to the rotor shrink temperature and tends to be scratched during the assembly of the rotor on the shaft.
One of the objects of this invention is to provide a rotor assembly which has superior rust resistance as compared with rotor assemblies known heretofore, and a method of manufacturing the rotor.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.